New York (CNN) -- CNN's Lou Dobbs stepped down from his controversial role as an advocacy anchor at the network at the end of his show Wednesday night, saying he plans to seek a more activist role.

"Over the past six months, it has become increasingly clear that strong winds of change have begun buffeting this country and affecting all of us, and some leaders in media, politics and business have been urging me to go beyond the role here at CNN and to engage in constructive problem-solving as well as to contribute positively to a better understanding of the great issues of our day and to continue to do so in the most honest and direct language possible," Dobbs said during his 7 p.m. broadcast.

Dobbs, 64, said he had discussed the issue with CNN President Jonathan Klein, who had agreed to a release from his contract "that will enable me to pursue new opportunities."

In a written statement, Klein called Dobbs "a valued founding member of the CNN family."

"For decades, Lou fearlessly and tirelessly pursued some of the most important and complex stories of our time, often well ahead of the pack," Klein said. "All of us will miss his appetite for big ideas, the megawatt smile and larger-than-life presence he brought to our newsroom, and we're grateful to have known and worked with him over the years.

"With characteristic forthrightness, Lou has now decided to carry the banner of advocacy journalism elsewhere. We respect his decision and wish him, Debi [Dobbs' wife], and his family the very best."

Dobbs, who is the last of the 29-year-old network's original anchors, said he was considering "a number of options and directions."

He cited the growth of the middle class, the creation of jobs, health care, immigration policy, the environment, climate change and the U.S. military involvement in Iraq and Afghanistan as "the major issues of our time."

But, he said, "Each of those issues is, in my opinion, informed by our capacity to demonstrate strong resilience of our now weakened capitalist economy and demonstrate the political will to overcome the lack of true representation in Washington, D.C. I believe these to be profoundly, critically important issues and I will continue to strive to deal honestly and straightforwardly with those issues in the future." Read Dobbs' full statement about his departure from CNN

Those issues, he added, are defined in the public arena "by partisanship and ideology rather than by rigorous, empirical forethought, analysis and discussion," and he vowed to work to change that.

In an e-mail to CNN staff members, Klein described the parting as "extremely amicable," and said Dobbs' replacement would be announced soon.

Dobbs was with Cable News Network from its initial broadcasts in 1980, acting as chief economics correspondent and host of the business program "Moneyline."

His coverage of the 1987 stock market crash won him the George Foster Peabody Award for excellence in broadcasting. That was one of many awards he received while at CNN, including an Emmy for Lifetime Achievement that he received from the National Academy of Television Arts and Sciences in 2005.

Dobbs left the network in 1999 to found SPACE.com, a Web site devoted to space-related subjects. He returned to the network in 2001 as anchor and managing editor of CNN's Moneyline News Hour, which became Lou Dobbs Tonight. He also acted as lead business news anchor for CNN/U.S. and CNNfn, the forerunner of CNNMoney.

During his second stint at CNN, Dobbs positioned himself as "tough, relentless, independent," lashing out at what he described as the deficiencies and "partisan nonsense" of both major political parties, and injecting advocacy journalism into his coverage of topics ranging from free trade to immigration.

His no-holds-barred, sometimes acerbic style brought him a loyal following, but also attracted controversy both to him and to the network, especially over the subject of illegal immigrants.

Dobbs will continue as anchor of The Lou Dobbs Show, a daily radio show that began in March 2008 and is distributed to more than 160 stations nationwide by United Stations Radio Networks Inc.